*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19850
19860
19873
198814
19891
19903
19915
19925
19936
19941
19959
199615
199711
19981
19991
20000
20011
20024
20030
20040
20050
20061
20070
20080
20090
20101
20111
20120
20130
20140
20150
20160
20170
Total84